This application is related to and claims priority from Japanese Patent Application No. 2002-232516 filed on Aug. 9, 2002, the content of which is hereby incorporated by reference.
1. Field of the Invention
The present invention relates to a vehicle air conditioner with front and rear air-conditioning units. Generally, the front air-conditioning unit is automatically operated, and the rear air-conditioning unit is manually operated.
2. Description of Related Art
A dual air conditioner for a vehicle is constructed with a front automatic air-conditioning unit and a rear manual air-conditioning unit. The front automatic air-conditioning unit automatically controls an air temperature in a front air-conditioning area (front seat area) of a passenger compartment to a front set temperature by heating and cooling air. The rear manual air-conditioning unit controls an air temperature in a rear air-conditioning area (rear seat area) of the passenger compartment to a rear set temperature that is manually set by a passenger on a rear seat in the passenger compartment. However, in the dual air conditioner, when a rear warm-air outlet is provided adjacent to the front seat area of a front center console, the following problem is caused. For example, in a case where a comfortable air-conditioning state is maintained by the front automatic air-conditioning unit in the front air-conditioning area, if a rear heater of the rear manual air-conditioning unit is operated, warm air from the rear warm-air outlet flows into the front air-conditioning area. Therefore, the comfortable air-conditioning state of the front air-conditioning area of the passenger compartment cannot be maintained. Further, the air temperature in the front air-conditioning area is controlled by the front automatic air-conditioning unit based on the temperature detected by a front temperature sensor, so that the front air-conditioning area is maintained at the front set temperature comfortable for the passenger on the front seat. However, when the front temperature sensor is disposed in an instrument panel portion, a temperature change due to the rear manual air-conditioning unit cannot be rapidly detected by the front temperature sensor. In this case, the air-conditioning feeling given to the passenger on the front seat is worsened.
It is an object of the present invention to provide a vehicle air conditioner capable of controlling an air temperature in a front seat area of a passenger compartment to a set temperature when a rear air-conditioning unit is operated during operation of a front air-conditioning unit.
According to the present invention, a vehicle air conditioner includes a front air-conditioning unit and a rear air-conditioning unit. The front air-conditioning unit includes a front air-conditioning case having an air introduction port for introducing air outside a passenger compartment and air inside the passenger compartment and an air outlet from which air is blown toward a front seat area of the passenger compartment, a front blower for blowing air introduced from the air introduction port, a front heater for heating air blown from the front blower, a front adjustment unit for adjusting an air heating amount by the front heater, a detecting unit for detecting an environment condition including at least an inside temperature of the passenger compartment and an outside temperature of air outside the passenger compartment, a temperature setting unit for setting a set temperature in the passenger compartment, and a control unit for determining a target air temperature blown toward the front seat area based on the set temperature and the environment condition detected by the detecting unit, and for determining at least one of an air blowing capacity of the front blower and an adjustment amount of the front adjustment unit based on the target air temperature. On the other hand, the rear air-conditioning unit includes a rear blower for introducing and blowing air inside the passenger compartment, a rear heater for heating air blown by the rear blower, a rear setting unit for manually setting one of a blowing capacity of the rear blower and a heating capacity of the rear heater. In the vehicle air conditioner, the control unit decreases the target air temperature in accordance with a decrease of the outside temperature detected by the detecting unit, when the outside temperature is lower than a predetermined temperature. Accordingly, when the rear heater of the rear air-conditioning unit operates while the front air-conditioning unit operates, the automatic control of the front air-conditioning unit is difficult to be affected by the operation of the rear heater. Therefore, the automatic control of the front air-conditioning unit can be accurately performed. Generally, the control unit corrects the target air temperature by a correction value so that the target air temperature becomes lower as one of the blowing capacity and the heating capacity set by the rear setting unit increases, and determines at least one of the blowing capacity of the front blower and the adjustment amount of the front adjustment unit based on the corrected target air temperature. In this case, the front blower and the adjustment amount of the front adjustment unit can be accurately controlled in accordance with the corrected target air temperature. Therefore, the thermal feeling given to the passenger on a front seat in the passenger compartment can be effectively improved.
Specifically, in a low outside air temperature lower than the predetermined temperature, the target air temperature for the front air-conditioning unit is controlled to be reduced by changing the correction value at a minus side. Therefore, even if the rear heater of the rear air-conditioning unit is operated, the air temperature to be blown toward the front seat area of the passenger compartment can be controlled at the set temperature.